Heat dissipation device

ABSTRACT

A heat dissipation device includes a plurality of fins stacked together, a plurality of heat pipes extending through the fins, and solder filled in gaps between the fins and the heat pipes. Each fin includes a plate defining a plurality of holes therein for extension of the heat pipes therethrough, respectively. A collar extends from a periphery of each of the holes. The collar includes a columned portion attached to an outer surface of each of the heat pipes, and a taper portion interconnecting the plate and the columned portion. The solder fills in a gap between the columned portion and a corresponding heat pipe and a space between the taper portion and the corresponding heat pipe. The collar has a height slightly smaller than a distance between two adjacent fins.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a heat dissipation device incorporatingheat pipes and fins, and more particularly to a combination structure ofthe fins which is used for combining the fins and the heat pipestogether.

2. Description of Related Art

Computer electronic components, such as central processing units (CPUs),generate large amounts of heat during normal operation. If the heat isnot properly dissipated, it can adversely affect operational stabilityof the electronic components and damage associated electronic devices. Aheat dissipation device is often attached to a top surface of a CPU todissipate heat therefrom.

Conventionally, a heat dissipation device as shown in FIG. 3 includes aplurality of fins 90 stacked together. A plurality of holes 91 andcollars 92 extending from edges of the holes 91 are formed by punching(or other means) of the fins 90. Heat pipes (not shown) extend throughthe holes 91, with a part of outer surfaces of the heat pipes attachedto the collars 92. Solder (not shown) is filled in gaps existed betweenthe collars 92 and the heat pipes to secure the heat pipes in the holes91 and increase heat transfer efficiency from the heat pipes to the fins90. A distance, which is indicated by P1, is defined between every twoadjacent fins 90, functioning as a channel for air flowing therethrough.

Due to a limited ductility of the fins 90 which are made of metallicmaterial, a height of the collars 92, which is indicated by H1 in FIG.3, cannot be as high as the distance P1, since such a large height mayresult in a break of the collars 92. Therefore, a bottom of each collar92 is spaced from an adjacent fin 90. The collars 92 such configuredcannot retain enough solder therein, which causes the solder to flowfrom bottoms of the collars 92 onto an adjacent fin during the solderbeing filled in the gaps between the collars 92 and the heat pipes. Theoverflowed solder is not only a waste of material, but also a negativeimpact to an aesthetic appearance of the heat dissipation device.

What is needed, therefore, is an improved heat dissipation device whichcan overcome the described limitations.

SUMMARY OF THE INVENTION

A heat dissipation device includes a plurality of fins stacked together,a plurality of heat pipes extending through the fins, and solder filledin gaps between the fins and the heat pipes. Each fin includes ahorizontal, flat plate defining a plurality of holes therein forextension of the heat pipes therethrough, respectively. A collar extendsfrom a periphery of each of the holes. The collar includes a columnedportion attached to an outer surface of the heat pipe, and a taperportion interconnecting the plate and the columned portion. A height ofthe collar approaches to a distance between two adjacent fins. The taperportion has an inner surface facing towards the heat pipe. A portion ofthe solder is retained in a space between the inner surface of the taperportion of the collar and the heat pipe to prevent the portion of thesolder from overflowing to the horizontal, flat plate of the fin.

Other advantages and novel features of the present invention will becomemore apparent from the following detailed description when taken inconjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present apparatus can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present apparatus. Moreover,in the drawings, like reference numerals designate corresponding partsthroughout the several views.

FIG. 1 is an assembled, isometric view of a heat dissipation device inaccordance with a preferred embodiment of the disclosure.

FIG. 2 is a cross-sectional view of the heat dissipation device of FIG.1, taken along line II-II thereof.

FIG. 3 is a side elevation view of a related heat dissipation device,with heat pipes thereof being removed.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIGS. 1-2, a heat dissipation device in accordance with apreferred embodiment of the disclosure comprises a plurality of fins 10stacked together, and a plurality of heat pipes 20 extending through thefins 10. Bottom ends of the heat pipes 20 are used to connect with abase (not shown) which is attached to a heat generating component (notshown), such as a CPU. Heat generated by the heat generating componentis transferred by the heat pipes 20 to the fins 10 and dissipated by thefins 10 to ambient air.

Each fin 10 has a rectangular thin plate 11 and two flanges 12 bentdownwardly from two long sides of the plate 11. The thin plate 11 ishorizontal and flat. A channel 13 is defined between every two adjacentfins 10 by the flanges 12. The channel 13 has a height which isindicated by P in FIG. 2. A plurality of round holes 19 (six in thisembodiment) is defined in each plate 11. A collar 16 extends from aperiphery of each hole 19. The collar 16 has a funnel-like shape. Thecollar 16 comprises a columned portion 14 and a taper portion 15interconnecting the plate 11 and the columned portion 14. The columnedportion 14 is cylindrical. The taper portion 15 is substantially atruncated cone with a small bottom thereof connecting a top of thecolumned portion 14, and a big top thereof connecting the plate 11. Thecollar 16 has a height in an axial direction of the hole 19 (i.e., anaxial direction of the heat pipes 20) which is indicated by H. Theheight H of the collar 16 approaches to the height P of the channel 13.That is, a distance between a bottom of the columned portion 14 and anadjacent underlying fin 10 along the axial direction of the hole 19 isvery small. A height of the columned portion 14 is substantially equalto that of the taper portion 15.

Each heat pipe 20 has a round cross section. The heat pipe 20 has wickstructures (not shown) formed in an inner surface thereof and workingfluid (not shown) contained therein.

In assembly, the fins 10 are stacked together. The flanges 12 of eachfin 10 abut against a lower, adjacent fin 10. Solder 30 is spread oninner surfaces of the columned portions 14 of the collars 16 of the fins10. The heat pipes 20 are then inserted into the holes 19 of the fins10. By the provision of the taper portions 15 which are located veryclose to the bottoms of the columned portions 14 of the correspondingupper collars 16, excessive solder 30 which is pushed out of thecolumned portions 14 is immediately received in the taper portions 15,thereby eliminating the possibility that the excessive solder 30 willdrop on the flat plates 11. Then, the fins 10 together with the heatpipes 20 are put into an oven to be heated. The solder 30 on the heatpipes 20 and located corresponding to the columned portions 14 of thecollars 16 is heated to flow. The flowed solder 30 evenly fills in gapsbetween the inner surfaces of the columned portions 14 of the collars 16and the heat pipes 20. After cooled, the solidified solder 30 thermallyand mechanically connects the heat pipes 20 and the columned portions 14of the collars 16 together. The solder 30 on the heat pipes 20 andlocated between the columned portions 14 is heated to flow downwardlyinto spaces between inner surfaces of the taper portions 15 of thecollars 16 and the heat pipes 20 as shown in FIG. 2. After cooled, thesolidified solder 30 thermally and mechanically connects the taperportions 15 of the collars 16 and the heat pipes 20 together whereby thethermal and mechanical connections between the fins 10 and the heatpipes 20 are reinforced. In the present invention, by the provision ofthe taper portions 15 and the design that the bottom of the columnedportion 14 is very close to a corresponding lower taper portion 15, thesolder 30 will not drop or flow to the horizontal, flat plate 11 tounfavorably affect an aesthetic appearance of the heat dissipationdevice.

The formation of the taper portions 15 results in an increasing of atotal height H of the collars 16 along the axial direction of the heatpipes 20. That is, the distance between bottoms of the columned portions14 and the adjacent underlying fin 10 is decreased, which could preventthe solder 30 from spraying onto the horizontal, flat plate 11 of theadjacent underlying fin 10. Furthermore, the taper portions 15 connectto the outer surfaces of the heat pipes 20 by the solder 30 retained inthe spaces therebetween. Therefore, a contact surface between the fins10 and the heat pipes 20 is increased, which is an advantage ofenhancing the heat dissipation efficiency of the heat dissipationdevice.

The heat pipes 20 are round in this embodiment, and the collars 16 formcorresponding columned portions 14 to contact with the heat pipes 20. Itis to be understood that the shape of the heat pipes 20 and the collars16 could be potentially varied, as long as the collars 16 comprise acontacting portion attached to the heat pipes 20 and an intermediateportion interconnecting with the plate 11 and the contacting portion,wherein a cross section of the intermediate portion has a size largerthan that of the contacting portion. In an alternative embodiment, thesolder 30 can be replaced by thermally conductive glue. When thethermally conductive glue is used, the step of heating the fins and theheat pipes in the oven can be omitted.

It is believed that the present invention and its advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A heat dissipation device comprising: a heat pipe; and a plurality offins stacked onto the heat pipe along an axial direction of the heatpipe, each fin comprising a plate defining a hole for extension of theheat pipe therethrough and a collar extending from a periphery of thehole, the collar comprising a columned portion attached to an outersurface of the heat pipe, and a taper portion interconnecting the plateand the columned portion, the taper portion increasing a height of thecollar along the axial direction of the heat pipe.
 2. The heatdissipation device as claimed in claim 1, wherein the height of thecollar is slightly smaller than a distance between two adjacent fins. 3.The heat dissipation device as claimed in claim 1, wherein a height ofthe columned portion is similar to that of the taper portion.
 4. Theheat dissipation device as claimed in claim 1, wherein the taper portionhas a truncated cone configuration, with a small bottom thereofconnecting a top of the columned portion, and a big top thereofconnecting the plate.
 5. The heat dissipation device as claimed in claim1, further comprising solder filled in gaps between the collars of thefins and the heat pipe.
 6. The heat dissipation device as claimed inclaim 5, wherein the taper portion has an inner surface facing towardsthe outer surface of the heat pipe and a portion of the solder isretained between the inner surface of the taper portion and the outersurface of the heat pipe.
 7. The heat dissipation device as claimed inclaim 1, further comprising thermally conductive glue filled in gapsbetween the collars of the fins and the heat pipe.
 8. A heat dissipationdevice comprising: at least one heat pipe; a plurality of fins stackedonto the at least one heat pipe along an axial direction of the at leastone heat pipe, with a channel defined between every two adjacent fins,each fin comprising a plate defining at least one hole for extension ofthe at least one heat pipe therethrough and a collar extending from aperiphery of the at least one hole, the collar comprising a columnedportion attached to an outer surface of the heat pipe, and a taperportion interconnecting the plate and the columned portion, a height ofthe collar being slightly smaller than a height of the channel; andsolder filled in gaps between the collars of the fins and the at leastone heat pipe, the solder filling in a gap between the columned portionand the at least one heat pipe and a space between the taper portion andthe at least one heat pipe.
 9. The heat dissipation device as claimed inclaim 8, wherein the columned portion is cylindrical, and the taperportion has a truncated cone shape, with a small bottom thereofconnecting a top of the columned portion, and a big top thereofconnecting the plate.
 10. The heat dissipation device as claimed inclaim 8, wherein a height of the columned portion is similar to that ofthe taper portion.
 11. A heat dissipation device comprising: at leastone heat pipe; a plurality of fins stacked onto the at least one heatpipe along an axial direction of the at least one heat pipe, each fincomprising a plate defining at least one hole for extension of the atleast one heat pipe therethrough and a collar extending from a peripheryof the at least one hole, the collar comprising a contacting portionattached to an outer surface of the at least one heat pipe, and anintermediate portion interconnecting the plate and the contactingportion, a cross section of the intermediate portion being larger thanthat of the contacting portion; and solder filled in gaps between thecollars of the fins and the at least one heat pipe, the solder fillingin a gap between the contacting portion and the at least one heat pipeand a space between the intermediate portion and the at least one heatpipe.
 12. The heat dissipation device as claimed in claim 11, whereinthe contacting portion has a columned shape for enclosing the outersurface of the at least one heat pipe, and the intermediate portion hasa taper shape with a small bottom thereof connecting a top of thecontacting portion, and a big top thereof connecting the plate.
 13. Theheat dissipation device as claimed in claim 11, wherein a height of thecollar approaches to a distance between two adjacent fins.
 14. The heatdissipation device as claimed in claim 11, wherein a height of thecontacting portion is similar to that of the retaining portion.